1. Field of the Invention
The present invention relates generally to a system for the removal of airborne contaminants. In particular, the present invention to a system in effluent air streams from outdoor paint booths, sand blasting facilities and the like.
2. Description of the Prior Art
The effluent air streams from industrial and military paint booths, such as an outdoor facility for painting an aircraft, and the like may contain a number of airborne contaminants. The constitution of these contaminants depends upon the particular paints and solvents which are utilized, but typically an array of both water insoluble contaminants and water soluble contaminants is present. Examples of water insoluble contaminants which might be present include hexanes, heptanes, octanes, nonanes xylenes, naphthas and mineral spirits. Examples of water soluble contaminants which might be present would include alcohols, ketones, esters and others. Other contaminants may include water soluble but high boiling substances such as glycol ethers. Airborne particulate contaminants may also be present.
The statutes, laws and regulations of the United States and the various state governments provide for strict clean air standards. The United States Environmental Protection Agency, for example, which is responsible for enforcing the United States government clean air standards mandates strict adherence to these standards by industry, the military, state and local municipalities and the like. These standards, for example, require the removal of solvents and other contaminants which are harmful to clean air from the effluent air steams from paint booths and the like prior to venting these streams to the atmosphere.
The aircraft, ship building and auto industries have had difficulty in meeting clean air objectives while avoiding excessive operating cost. The magnitude of painting processes in these industries and, in particular, the spray painting processes, produce a very large air and contaminant flow which is difficult to treat economically by conventional contaminant removal processes. Higher operating cost are ultimately passed on to the end user of the product.
The technology of unit operations capable of performing specific separation functions for most chemicals at commonly encountered operating conditions is well known in, for example, the chemical engineering art. The art has not heretofore known, however, a satisfactory system for removing airborne contaminants from the effluent air streams of paints booths and the like, and especially from the effluent air streams from spray paint booths of the sort used in the aircraft, ship building and auto industries.
Accordingly, there is a need to provide an improved system for removing airborne contaminants from the effluent air streams from spray paint booths of the sort used in the aircraft, ship building and auto industries which is substantially less expensive and yet is very efficient and highly reliable.